<!DOCTYPE html>
<html>
<head>
<script>
function doe() {
document.getElementById('b').setAttribute('style', 'position: absolute;');
document.body.offsetHeight;
document.body.setAttribute('style', 'position: relative;');
document.body.offsetHeight;
document.getElementById('b').setAttribute('style', '');
}
setTimeout(doe,0);
</script>
</head>
<body>

<span style="position: relative; ">
<div>
<div id="b">
</div>
</div>
</span>
</body>
</html>
